1. Field of the Invention
The present invention relates to an ultrasonic testing method used to perform phased array ultrasonic testing (the term “ultrasonic testing” is hereinafter abbreviated as UT).
2. Description of the Related Art
In phased array UT, an object is examined for any internal imperfection by the multiple ultrasonic elements (hereinafter called elements) of an array sensor (hereinafter sensor) sending ultrasonic waves asynchronously and changing the point at which the ultrasonic waves reach at the same time (focal point) (see JP-2014-106130-A). Each element of the sensor is connected to a transmission circuit (pulser) of a UT device (phased array UT device) in a one-to-one correspondence relationship via a connector. The element sends ultrasonic waves by being excited by the pulsers ome UT devices have more connectors than they have pulsers and a switch circuit (e.g., relay circuit) used for switching the connections between the pulsers and the connectors. In such a UT device, multiple sensors are connected to the device, and the connections between the pulsers and the connectors, that is, the sensors that are to be electrically connected to the pulsers are sequentially switched (see JP-1998-311822-A).